Cancer of the prostate is the most commonly diagnosed neoplasm in men with over 232,000 new cases estimated in the United States in 2005, i.e., 30% of all new cancer diagnoses in men. Mortality from prostate cancer remains a significant problem with current treatment(s) with an estimated 30,350 deaths from prostate cancer in 2005 making it the second leading cause of cancer death in men after lung cancer.
Lung cancer is the leading cause of cancer death in both men and women in the United States, and this same trend is seen in many other countries. In the United States in 2004 it was estimated that lung cancer accounted for 31% of cancer deaths in men and 25% of cancer deaths in women. Small-cell lung cancers account for 20% to 25% of all lung cancers. Small-cell lung cancer differs from other lung cancers in that it metastasizes very early and can rarely be cured surgically. In the current management of small-cell lung cancers the majority of patients are treated first with chemotherapy plus radiotherapy, but with this combination survival is only 20% at 3 years. There is an increased incidence of secondary cancers with the cisplatin- and cytoxan-based regimens used to treat small-cell lung cancer, and the chemotherapeutic regimens for small-cell lung cancer containing doxorubicin may induce cardiac myopathy. All the presently utilized chemotherapeutic agents for treatment of small-cell lung cancers have some side-effects, including myelosuppression. Atrial natriuretic peptides consist of a family of peptides that are synthesized by three different genes then stored as three different prohormones [i.e., 126 amino acid (a.a.) atrial natriuretic peptide (ANP), 108 a.a. brain natriuretic peptide (BNP), and 103 a.a. C-type natriuretic peptide (CNP) prohormones] (8-10). Within the 126 a.a. ANP prohormone are four peptide hormones i.e., long acting natriuretic peptide (LANP), vessel dilator, kaliuretic peptide, and atrial natriuretic peptide (ANP), whose main known biologic properties are blood pressure regulation and maintenance of plasma volume in animals and humans. The BNP and CNP genes, on the other hand, appear to each synthesize only one peptide hormone within their respective prohormones, i.e., BNP and CNP. Each of these peptide hormones circulates in healthy humans with vessel dilator and LANP concentrations being 17- to 22-fold higher than ANP, 33- to 48-fold higher than BNP and 124 to 177-fold higher than CNP.
Therefore, what is needed is a method of treating cancer that can both improve survival, lacks the side effects of current therapies, and ultimately decrease morbidity.